Auxiliary dynamotor for the ignition system of an internal combustion engine



July 30, 19-63 Origihal Filed Aug. 2

5. R. M CLURE AUXILIARY DYNAMOTOR FOR THE IGNITION SYSTEM 60F :NINTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 1 INVENTOR. STANLEY R. MCLUREATTORNEY July 30, 1963 s. R. McCLURE 3,099,772

AUXILIARY DYNAMOTOR FOR THE IGNITION SYSTEM OF AN INTERNAL COMBUSTIONENGINE Original Filed Aug. 26, 1959 2 Sheets-Sheet 2 INVENTOR. STANLEYR. M CLURE ATTORNEY 3,099,772 AUXILIARY DYNAMOTQR FOR THE IGNITIQNSYSTEM F AN TNTERNAL COMBUSTHUN EN- GINE Stanley R. McClure, Rowena, Ky.Continuation of abandoned application Sac. No. 836,299,

Aug. 26, 1959. This application Mar. 15, 1963, Ser- No. 266,776

3 (Zlaims. (l. 3152l8) This invention relates to an improved ignitionapparatus for internal combustion engines.

This application is a continuation of my copending application SerialNo. 836,299 for Ignition Apparatus filed August 26, 1959 which is acontinuation in part of my co-pending application Serial No. 758,523 forDynamo compensator for DO Jump Spark Ignition, filed September 2, 1958,now abandoned, and of co-pending application Serial No. 835,521 filedAugust 24, 1959, her Ignition System, now 2,998,470.

It is well known that in the conventional ignition system ordinarilyutilized in automotive vehicles that the time allowed for producingnecessary spark varies inversely with the speed of the engine.Consequently at low speed the sparking interval is relatively long whileat high speed it is relatively short. An inherent weakness in such asystem is that spark current diminishes as the engine speed increasesand at high speed decreases to such an extent that the effectiveness ofthe spark is seriously impaired. This phenomenon is termed spark fadeand is due to reaotance caused by the high frequency of spark requiredat high speed. This action occurs because magnetic flux can be built upin the core of the induction coil only during the intervals when thebreaker points are closed. The time length of these intervals diminshesas the engine speed increases, and as a consequence the sparkinginterval at high speed is not sufficiently long to enable magnetism tobe built up in the core of the induction coil to the same degree that itcan in the longer interval available at lower engine speed. Thus whenthe engine is running at high speed the sparking interval is reduced tosuch an extent as to cause corresponding reduction of intensity andresultant inefliciency of the spark with a proportional decrease in thepower of the engine.

An important object of the present invention is to pro vide a simple andautomatic means for maintaining uniform sparking efficiency in theignition circuit under varying conditions of speed of the engine thanhas heretofore been practiced.

Another important object of this invention is to provide a means for usewith conventional battery ignition systems which provide :a higher sparkvoltage as speed increases.

Still another object of this invention is to provide a compensatingmeans for the conventional battery ignition system that :at apredetermined speed will become stable in output.

Still another object of this invention is to provide a means for usewith compensating means for a conventional battery ignition system whichprovides higher spark voltage upon starting the engine.

The difficulties referred to above, i.e., fading of spark voltage withincrease in speed due to the reactance of the induction coil have beenfor the most part overcome by the use of the apparatus disclosed in myco -pending application, S.N. 758,523, previously referred to. Thisdevice in brief consisted of a small dynamo serially installed in theprimary circuit of (3. conventional battery ignition system with itsarmature driven by the engine and its electromagnetic field furnished bya winding across the battery. Since the armature of the dynamo is drivenat .the gaps of the spark plugs.

a speed proportional to the speed of the engine the voltage produced isproportional to the speed of the engine. Thus as sparking frequency isincreased due to high engine speed, the voltage is increased tocompensate for increased reactance at the induction coil. At idlingspeeds an inconsequential amount of voltage is produced so that thesystem compensates automatically to variations in engine speed. It wasfound, however, that although this was an exemplary improvement overprior methods that at high engine speed the spark voltage was at timesstill erratic. It was determined that the erratic spark was due toreactance of the armature of the dynam c.

It was discovered that this defect could be eliminated by theinstallation of a relatively large condenser connected to the brushes ofthe auxiliary dynamo, or across the ignition source at a point betweensaid dynamo and the spark coil. By relatively large it will beunderstood that the conventional condenser installed in close proximityto the contacts is of one-half to one rnicrofarad in size. I have found,however, that the capacity of my auxiliary condenser attached at thepoints indicated above should be to 800 times as great as the conventialcondenser. The preferred capacity is in a range of from 200 to 400microfarads. Larger condensers may be utilized and as a matter of fact Ihave utilized 500 and 600 microfarad condensers which operate quiteefliciently but show no improvement over the 400 microfarad condensers.

The installation of the auxiliary dynamo and condenser causes anincrease in resistance which under normal conditions of temperature isnegligible. However, in extremely cold weather, this added resistancemay cause difficulty in starting the motor since operation of thestarter, in turning over the cold engine, consumes a very substantialpercentage of the power output of the battery. This causes a severe dropin potential at For maximum starting efliciency, the spark plugpotential should be at a maximum while the starter is in operation,since as is well known, the current required to turn over the engine incold weather will quickly deplete the battery voltage. To compensate forthis condition, one embodiment of my invention utilizes an armature ofthe auxiliary dynamo, comprising a core and two commutators, commonlytermed a dynamotor, in which one of the commutator brushes is connectedby means of a switch to the battery. This commutator acts as .a motorwhile the other commutator acts as a generator. The shaft of thearmature which under normal conditions is driven by the engine, isconnected to a clutch disengaged from the engine when it is not running.A suitable clutch might be an overrunning clutch of the ratchet orroller type. Thus, upon closing of the starter switch onto the switchconnected to the brush of the motor commutator, voltage from the batteryspins the armature to impress additional voltage upon the spark coil inorder to provide a hot starting spark as the motor is turned over by thestarter. This places a drain of about 5 or 6 amps. upon the battery, andat the same time produces a hot spark which allows almost instantaneousstarting so that the overall drain on the battery is reduced.

The invention will be better understood by reference to the attacheddrawings.

Referring now to the drawings, FIG. 1 is a diagrammatic view of anelectric ignition system embodying the various features of my invention.

FIG. 2 is a diagrammatic view of a portion of a similar system showingthe condenser connected at a different point.

FIG. 3 is a diagrammatic view of a portion of a further modified systemin which a second field winding of the auxiliary dynamo has beenomitted.

FIG. 4 is a diagrarnmatical View of a specially modified armatureattached to an overnmning clutch.

Referring now to FIG. 1, the battery or direct current source isindicated by numeral 1. Connected to the battery are lines 2 and 3 andconnected across lines 2 and 3 is first electromagnetic field winding4-. The electromagnetic field produced by this winding energizes thedynamo, the armature of which is designated by numeral 5 and the brushesof which are designated by numeral 19. Connected to the two brushes is asecond field winding 6 which in one embodiment may be polarized to aidthe first field winding 5. In this embodiment, i.e., field 6 polarizedwith field 4, the magnetic strength of field winding 6 varies inproportion to the speed of revolution of the armature 5 so as toincrease the voltage impressed on the spark coil as the armature speedincreases. Numeral 7 designates a shaft connected to any accessoryengine shaft not shown. Numeral 2t designates a condenser connected tobrushes 19 of the accessory dynamo. Numeral 23 designates a lineconnected to brush 19 and resistor 24 which leads to the primary ofspark coil 12. Numeral 11 designates a onehalf microfarad condenserconventionally connected across the points or contacts 9 and 18 near theprimary of spark coil 12. Numeral 13 designates the iron core of sparkcoil and numeral 14 designates the secondary of spark coil. 15designates the spark plug. 8 designates a cam and numeral 25 designatesa spring utilized in conjunction with the breaker points. 16 designatesthe armature of the standard two brush generator, 17 designates thefield winding of said generator and 18 designates a voltage regulator ofthe generator. 21 designates the ignition switch.

\As previously indicated shaft 7 is a mechanical means which connectswith the armature 5 of the accessory dynamo and an accessory enginedriven shaft. This may be an extension of the shaft of the standardgenerator. The armature 5 of the accessory dynamo may be driven by aconventional V :belt drive connected to an engine driven shaft so thatthe speed of the armature is in proportion to the speed of the engine.In this manner the output of the dynamo is proportional to the speed ofthe engine and the system automatically compensates to variation inengine speed. As previously indicated another embodiment of my inventionwhich is shown in FIG. 1 involves second field winding 6 polarized inopposition to field winding 4. In this embodiment the magnetic strengthof field winding 6 is essentially nil at zero rpm. whereas the magneticstrength produced by field winding 4 is essentially constant at allengine speeds deriving its strength from the battery. Increase in speedproduces aditional current until a predetermined speed is reached. Thisallows an increased spark at low speed so that full horsepower isavailable for the engine on hills and for fast acceleration. However, asspeed is increased to a predetermined point magnetic field winding 6 inopposition to magnetic field winding 4 stabilizes the voltage. Thiseifectively governs the maximum voltage of the system.

FIG. 2 is a modification of FIG. 1 showing the accessory condenser 20connected at a diflierent position. As previously indicated, thiscondenser is preferably of a capacity of 200 to 400 microfarads.However, larger condensers may be utilized if desired.

In FIG. 3 the second electromagnetic field winding 6 has been omitted.It will be noted that in FIG. 3 the condenser is connected in a positionanalogous to FIG. 1.

In operation the condenser 2% connected to the brushes of the auxiliarydynamo, or across the ignition source at a point between the brush 19and the spark coil 12, as shown in the drawings, acts as a powerreservoir and thereby prevents the armature of the accessory dynamo frombeing affected by the frequency of discharge caused by opening andclosing of the breaker points at high engine speed. In eiiect, thecondenser acts as a cushion to protect the armature from the constant hih speed 4 discharge caused by the frequency of sparking, common withtodays high horsepower engines.

Referring now to FIG. 4, 27 designates the shaft of the armature.Numerals 23 and 29 designate commutators and 3t) designates the core ofthe armature. 22 designates the brushes of the motor commutator 28.Numeral 19 designates the brushes of generator commutator 29. Numeral 31designates an overrunning clutch of the ratchet type which is attachedto a shaft of the engine, not shown. Similarly, a roller clutch may beutilized instead of the ratchet clutch. A brush 22 of commutator 28 isconnected by way of switch 35 and starter switch 31., to the battery 1.The starter motor is designated by numeral 33. Brush 19 of commutator 29is connected by way of ignition switch 21 to battery 1. Thecorresponding brush 19 of commutator 29 is connected by line 23 to sparkcoil not shown. Field winding 4 connected between lines 2 and 3 producesa magnetic field which energizes the armature. In operation, uponclosing of starter switch 32, onto switch 35, voltage from battery 1 isimpressed upon motor commutator 28 via brush 22 and spins shaft 27,disengaged by clutch 31 from the driving means. The voltage produced bythe revolution of the armature is carried by the line 23 to the primaryof the spark coil, not shown, to produce a hot arting spark.Simultaneously, starter motor 33 turns over the engine to start theengine.

Upon starting of the engine, clutch 31 via driving means not shown,engages with shaft 27 to turn the armature to produce voltageproportional to the speed of the engine in the manner previouslydescribed. Simultaneously, switches 32 and 35 are opened and motorcommutator 28 is disconnected from the circuit.

It is obvious that many modifications can be made from those shown inthe illustrations. The output of the dynamo may be varied to produce anessentially stable spark at all engine speeds and alternately to producean increased spark at increased engine speeds. The latter effect may bealso achieved by the addition of the second field winding 6 whenpolarized to aid the first field winding 4. In another embodiment thesecond field winding 6 may be polarized in opposition to field winding 4so as to allow increased spark at lower engine speeds while limiting thespark at high engine speed and thus governing the maximum voltageproduced. I have found that the invention increases engine efficiency,and increases gas mileage.

It is evident that the system shown may be further modified from thescope of the invention, therefore I do not wish to limit the inventionto the precise details herein illustrated and described.

I claim:

1. In an ignition system for use with a variable speed internalcombustion engine which includes a battery and three parallel circuitsacross the terminals of the battery in which:

(a) The first circuit contains a generator;

(12) The second is an ignition circuit and contains an ignition switch,a spark coil having a primary winding which is electricallyinterconnected in said circuit and interrupting means for making andbreaking the circuit;

(0) The third circuit is normally open and contains a starting motor andswitch means for closing the circuit when the ignition switch is closed,

means for providing a higher spar-k voltage upon starting and forincreasing sparking eificiency under increased conditions of speed whichcomprises: an auxiliary dynamo serially installed in the ignitioncircuit between the battery and the spark coil, said dynamo comprisingan enginedriven armature and magnetic means for providing a stablemagnetic field for said dynamo, said armature comprising (a) A motorcommutator and brushes in which one of said brushes is electricallyconnected to said third circuit;

(b) A core;

(c) A generator commutator and the brushes in which one of said brushesis connected to the primary winding of said spark coil,

in combination with clutch means operatively connected to said armatureand connectible to the engine so that said armature is disengaged fromthe engine and freely rotatable when the engine is not running.

2. In an ignition system for use with a variable speed internalcombustion engine, which includes a battery and two parallel circuitsacross the terminals of the battery in which:

(a) The first circuit contains a generator;

(15) The second circuit is an ignition circuit and contains an ignitionswitch, a spark coil having a primary winding, which is electricallyinterconnected in said circuit, interrupting means for making andbreaking the circuit and a first capacitor connected across saidinterrupting means,

means for providing increased sparking efficiency under conditions ofincreased engine speed which comprises:

(a) An auxiliary dynamo having brushes and an engine-driven armature,said auxiliary dynamo being serially connected in the ignition circuitbetween the battery and the spark coil;

(12) Magnetic means for-providing a stable magnetic field for saiddynamo; and

(c) A second capacitor connected in shunt across the brushes of saidauxiliary dynamo, said second capacitor having a capacitance of greaterthan microfarads.

3. In an ignition system for use with a variable speed internalcombustion engine, which includes a battery and two parallel circuitsacross the terminals of the battery in which:

(a) The first circuit contains a generator;

(b) The second circuit is an ignition circuit and contains an ignitionswitch, a spark coil having a primary Winding which is electricallyinterconnected in said circuit, interrupting means for making andbreaking the circuit and a first capacitor connected across saidinterrupting means,

means for providing increased sparking efficiency under conditions ofincreased engine speed which comprises:

(a) An auxiliary dynamo having brushes and an engine-driven armature,said auxiliary dynamo being serially connected in the ignition circuitbetween the battery and the coil;

(b) Magnetic means for providing a stable magnetic field for saiddynamo; and

(c) A second capacitor electrically interconnected in said circuit,across the battery, at a point between the auxiliary dynamo and thespark coil, said second capacitor having a capacitance of greater than150 rnicrofarads.

Knudson Apr. 29. 1959 Buon May 26, 1959

1. IN AN IGNITION SYSTEM FOR USE WITH A VARIABLE SPEED INTERNALCOMBUSTION ENGINE WHICH INCLUDES A BATTERY AND THREE PARALLEL CIRCUITSACROSS THE TERMINALS OF THE BATTERY IN WHICH: (A) THE FIRST CIRCUITCONTAINS A GENERATOR; (B) THE SECOND IS AN IGNITION CIRCUIT AND CONTAINSAN IGNITION SWITCH, A SPARK COIL HAVING A PRIMARY WINDING WHICH ISELECTRICALLY INTERCONNECTED IN SAID CIRCUIT AND INTERRUPTING MEANS FORMAKING AND BREAKING THE CIRCUIT; (C) THE THIRD CIRCUIT IS NORMALLY OPENAND CONTAINS A STARTING MOTOR AND SWITCH MEANS FOR CLOSING THE CIRCUITWHEN THE IGNITION SWITCH IS CLOSED, MEANS FOR PROVIDING A HIGHER SPARKVOLTAGE UPON STARTING AND FOR INCREASING SPARKING EFFICIENCY UNDERINCREASED CONDITIONS OF SPEED WHICH COMPRISES: AN AUXILIARY DYNAMOSERIALLY INSTALLLED IN THE IGNITION CIRCUIT BETWEEN THE BATTERY AND THESPARK COIL, SAID DYNAMO COMPRISING AN ENGINEDRIVEN ARMATURE AND MAGNETICMEANS FOR PROVIDING A STABLE MAGNETIC FIELD FOR SAID DYNAMO, SAIDARMATURE COMPRISING (A) A MOTOR COMMUTATOR AND BRUSHES IN WHICH ONE OFSAID BRUSHES IS ELECTRICALLY CONNECTED TO SAID THIRD CIRCUIT; (B) ACORE; (C) A GENERATOR COMMUTATOR AND THE BRUSHES IN WHICH ONE OF SAIDBRUSHES IS CONNECTED TO THE PRIMARY WINDING OF SAID SPARK COIL, INCOMBINATION WITH CLUTCH MEANS OPERATIVELY CONNECTED TO SAID ARMATURE ANDCONNECTIBLE TO THE ENGINE SO THAT SAID ARMATURE IS DISENGAGED FROM THEENGINE AND FREELY ROTATABLE WHEN THE ENGINE IS NOT RUNNING.